Not too sure about Linux but this will help for Vista -

http://www.computertechtips.net/64/make-firefox-4-look-like-ff-3-6/

and this -

http://www.mozilla.com/en-US/firefox/features/

Upgrading to Fx4 is no longer an option for security reasons. You should go to Fx5.

The appearance of Firefox on my Linux box hasn't changed, which is why I was asking. And this'll make you feel really good, I just found out about Firefox 4 less than 2 months ago and now it's Firefox 5. I found out about 4 when I was downloading Firefox onto a friends computer for her, and I wasn't too found of the new look then. The only question left then is does either site list a fix for 5 as well? Or does 5 go back to the base look/style of 3?

Although the security question is nearly moot in my case. The primary web surfing I do with my Vista box is for streaming videos on three different sites that I highly trust. I occasionally check my e-mail on it, but I predominantly use my Linux box for most web surfing since it's such a pain for someone to create a virus for Linux

Firefox 5 is essentially a security update for Firefox 4; I don't know of any layout changes.

User interface changes for Fx4 will work in Fx5.

Don't stay with Fx 3.6.8. At least go to 3.6.19 -

http://www.mozilla.com/en-US/firefox/all-older.html

@Razmoudah

Ubuntu comes with their own version of Firefox, plus Ubuntu versions of Firefox come with an Ubuntu Modifications extension. It may not be possible to make the Ubuntu version look exactly like the Windows version of Firefox. If you are using a different version (distro) of Linux, the same may be true. The best chance of getting Firefox to being identical is by using the Mozilla version of Firefox, but there will still be some differences, especially in the Menu layout; Edit > Preferences vs Tools > Options is the main difference. That holds true regardless of the version of Firefox involved.

@ alan_r: Thanks, that answered my question for me and I'll take a look at those sites the next time I get a chance.

@ the-edmeister: You really didn't pay close attention to what I was asking about earlier, did you? I stated that I didn't like the GUI (Graphic User Inerface) layout changes made to Firefox 4, and I had been asking for a means to modify the GUI layout of 4 to look like 3 as I preferred that GUI layout more, especially since I have 2, let me repeat that 2, computers, one running Linux, it is Ubuntu, and one running Microsoft's Windows (or as I prefer Microshit's Crapdos, all it gets is a lot of hype and most software developed specifically for it, both Apple's MacOs and Linux usually run better and do more with fewer system resources) Vista, for gaming compatibility and streaming video sites like The Anime Network or Netflix as their players don't like my Linux box, as the Linux boxes GUI layout is the same as the GUI layout for Firefox 3. Next time more carefully read the entire thread, as it is an insult to the person you are attempting to help when you give useless information because you couldn't be bothered to attempt to understand what the problem was. Hell, the thread title should've told you that the question was predominantly pertaining to making a newer version of Firefox for Window's have the GUI layout of an older version of Firefox for Window's. And if it makes you feel any better about trying to be an ass, only the original question was posted using my laptop, all of the rest of my views and posts have been done using my desktop, because that's what I normally check my e-mail with in the mornings.